Arrangements are known for the stretching and warping of thermoplastic warp thread, especially polyester thread, comprising a set of feed rollers, a heating arrangement and a set of take-off rollers which rotate at a greater circumferential speed than the feed rollers.
In such an arrangement (French public application No. 77,29618), prestretched polyester threads are taken from spools on a creel and combined as a thread sheet. These are then passed through a heating oven located between the feed rollers and the take-off rollers and are thereafter wound onto a warp beam. Since the free thread length between the two roller arrangements cannot exceed a certain length (otherwise the thread sheet cannot pass through the oven in a clearly defined path) the length of the oven is thus limited. In order to provide a sufficient amount of heat to the thread, the oven must be run at a comparatively high temperature. In the event the arrangement is stopped, for example, in consequence of a broken thread, the warp sheet segment in the oven is overheated. Even if this does not lead to the tearing of threads, nevertheless there occurs a certain inhomogeneity in the thread sheet which can, for example, lead to a different level of dye acceptance in a subsequent dyeing process.
A further arrangement for the formation and delivery of stretched synthetic ribbon material is disclosed in German published application No. 27,25,348. In this arrangement, a film of synthetic material is provided from a supply roller and is sliced in the longitudinal direction. The thus formed ribbons are led through a warming segment located between two sets of rollers and subsequent thereto they are utilized in a textile machine. The warming segment comprises a set of three heatable rollers. The ribbons are led around a portion of the circumference of these rollers. Regrettably, in this arrangement when the machine stops, the ribbons in the heating segment become overheated.
It is further known (Kettenwerk Praxis 3/76, pages 15-17) to slice a sheet of synthetic material in a longitudinal direction and to heat the thus formed ribbons by means of a heating plate placed between two sets of rollers, to stretch the ribbons and thereafter to warp the stretched ribbons on a warp beam. The heating plate can be moved from the operating position into an at-rest position activated by one of the ribbons. The ribbons have a width of at least one millimeter so that the separation between the two sets of rollers may be chosen to be a little bit larger than in a stretching arrangement for pre-stretched yarn.